Fig. 1.
Catalytically active antibodies (abzymes) used for testing. After precipitation with ammonium sulphate and affinity chromatography on protein-G sepharose, immunoglobulin (Ig)G preparations from patients with systemic lupus erythematosus (SLE) (upper row) or from immunized rabbits (lower row) were further purified by size exclusion-high performance liquid chromatography (HPLC-SEC) and the shaded fraction was collected (a) and used to prepare F(ab)2 fragments, subjected to polyacrylamide gel electrophoresis (PAGE) in denaturating and non-denaturating conditions (b), as well as testing for the presence of sialidase activity and its inhibition with 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DANA) (c).